json-repair

https://github.com/sashazykov/json-repair-rb

Repairs broken JSON: missing quotes and commas, unclosed brackets, trailing commas, unquoted keys, single quotes, comments, Python constants, NDJSON, Markdown code fences and list markers in LLM output, truncated documents, and more. A Ruby port of the jsonrepair JavaScript library — useful whenever JSON from LLMs, APIs, or logs does not strictly follow the standard.